THE EOCENE OF EUROPE AND NORTH AMERICA 127 



onictis, of the size of a puma (Felis concolor), with sectorial teeth, short face 

 and jaws. Another branch of oxyaenids includes animals of smaller size 

 (Oxyccna) with sharp and effective sectorials. Of the 

 Characteristic g^^e of the modern civets (Viverra) are several species 

 Mammals ^^ Sinopa, adapted to the quest of birds and small 



Coryphodonts mammals. Of great zoogeographic interest is the sim- 



Phenacodonts ultaneous distribution of three of these families (Palse- 



Meniscotheres onictidae, Mesonychidae, Hysenodontidse) in the Lower 



Tillodonts Eocene of France. 



Taeniodonts Progressive or m odernized mammals. — Contrasting with 



Insectivores these archaic, small, aberrant carnivores, are the mem- 



Arctocyonids bers of the family Miacidae, including Didymictis, sur- 



Mesonychids viving from the Torrejon, besides a great variety of small 



Palffionictids related carnivores {Viverravus, Miacis, Uintacyon, Vid- 



Oxyaenids pavus), all distinguished by the fact that the carnassial 



Hysenodontids teeth are the same as those in the modern Carnivora, 



Lemuroids namely, the fourth upper premolar and first lower molar. 



Rodents Evidently these small true pro-carnivores were begin- 



Dichobunoids i^ii^g to sharply compete for their prey with the small 



(Artiodactyls) creodonts, although the larger creodonts {Palceonictis, 

 Lophiodonts Pachyoena) were alone capable of attacking animals of 



Hyracotheres the size of Coryphodon and Phenacodus. The primates 



are now certainly recognized for the first time. Sur- 

 prisingly modern is the Tarsius-like Anaptofnorphus, a short-faced, large- 

 eyed, aberrant form, with teeth analogous to those in the existing tarsier 

 (Tarsius) of Madagascar, that is, not distinctly lemuroid. An insectivore 

 of the diprotodont type or with an enlarged pair of lower front teeth 

 is Cynodontomys, ancestral to the Microsyopidae of the Bridger, and with 

 some analogies to the Mixodectidae of the Torrejon and the Plesiadapidae 

 of the Cernaysian. Among the herbivorous ungulates the greatest interest 

 centers in the appearance of two families of even-toed or artiodactyl 

 forms, the Trigonolestidae, diminutive forms (Trigonolestes) with a typical 

 artiodactyl astragalus, perhaps related to the Dichobunidae {Protodicho- 

 hune) of the Upper Ypresian. Of more doubtful affinity are the sup- 

 posedly pig-like achaenodonts, represented by Parahyus, quite an un- 

 certain reference. Of equal moment is the sudden appearance of three 

 families of Ungulata-Perissodactyla, namely, the horses (Equidae), tapirs 

 (Tapiridae) , lophiodonts (Lophiodontidse) . The lophiodonts are represented 

 by the excessively slender-limbed and narrow-footed Heptodon, analogous 

 in size only to the Chasmotherium of the Ypresian of France, but distin- 

 guished by dolichocephaly. Known in America only, at this stage, are the 

 tapirs (Systemodoyi) , animals somewhat exceeding the modern foxes (Vidpes) 

 in size. Still more numerous and characteristic, as well as diversified, are 

 the horses, including eleven species which have been discovered in the 



